Millions of patients have surgical procedures or other conditions that require the placement of a tube or catheter in a body space for drainage of fluids and gases. For example, many chest disorders due to cancer, infection, heart disease, trauma, and other maladies require the temporary placement of a body-space drainage tube (also referred to as a body tube) into one or more spaces within the chest.
Coronary and heart-valve disease patients require temporary pleural and pericardial drainage in the post-operative period. Patients with lung disorders require temporary drainage of the pleural space due to pleural effusion. Patients suffering from chest trauma require various pleural interventions to treat collapsed and injured lungs. Patients with AIDS often have respiratory manifestations, many of which lead to effusions or pneumothoraces that require drainage from the chest.
A chest tube is a type of body-space drainage tube placed in the chest in a process known as tube thoracostomy. The chest tube is part of a drainage system that also comprises a drainage canister used to collect the drained fluids. In some cases, a vacuum is drawn out of the drainage canister to help expedite the drawing of fluids, gases, or both from the chest. While design advances have been made in the drainage canister, very little has changed with the chest tube itself.
FIG. 1 is an illustration of a common body-space drainage-tube system 2. The drainage-tube system 2 comprises one or more body tubes 10, corresponding coupler 12, a canister tube 14, a drainage canister 16, and a vacuum source 18. A body tube 10 is a long, semi-stiff, clear plastic tube having a body-tube distal end 11 that is inserted into the chest or other body space (or body cavity) and a body-tube proximal end 13 that extends outside of the body for coupling with the canister tube 14 via the coupler 12. The body tube 10 provides a fluid path from the body space to the canister tube 14, so as to drain fluid, gas, or both from the body space. In a system known as a closed-suction drainage system, additional components, such as a vacuum source 18 creates low pressure in the canister to draw the fluids, gases, or both out of the body space and into the drainage canister 16.
Body tubes 10 are used to treat may medical conditions. For example, if a lung is compressed due to a collection of fluid, the body-tube distal end 11 of a body tube 10 is inserted into the space between the pleura or within the mediastinum. This placement of a body tube 10 inside the chest drains the collection of fluid and allows the lung to re-expand.
Body tubes 10, especially the larger variety, are inserted mostly by surgeons, but also by pulmonologists, radiologists, critical-care physicians, primary-care doctors, and emergency personnel. Large diameter, large lumen body tubes drain thick pleural fluids more effectively than smaller tubes, in part because a bigger lumen can tolerate more debris without clogging than a smaller lumen. Large-diameter body tubes are not always well tolerated by the patient due to pain, however, and the inability to direct the insertion can lead to incorrect placement. Even the larger tubes can become clogged with blood clots and fibrinous material.
Bleeding often occurs after heart surgery or trauma. When this occurs, the blood can clot in the tube inside the patient, impairing the function of the body tube. Bleeding and clotting in the tube in this circumstance can be life threatening for two reasons. First, clinicians carefully monitor the amount of blood that comes out of the tube as a measure of the seriousness of the amount of bleeding. If blood pools in the chest, for example, then the measurement omits the pooled blood, because it is not draining through the body tube. The patient consequently can lose a large volume of blood without awareness of the health care practitioner and thus, without treatment for the blood loss. This blood loss can have severe hemodynamic consequences, including death. Second, if blood pools in the pericardial space, it can compress the structures of the heart, impairing the return of blood to the heart, and thus the ability of the ventricle to fill and empty. This condition, called pericardial tamponade, likewise can be fatal.
When clinicians caring for patients in the perioperative period following surgery and trauma notice a clot forming in the body tube, they often undertake various measures to try to remove the blood clot. One method is to simply tap the body tube to try to break up the clot. Another method is to “milk the tube,” which involves using fingers (or a rudimentary device made from a pair of pliers with added roller heads) to compress the body tube over the clot to break up the clot. This method has the effect of pulling some of the clot towards the canister tube 14 that goes to the drainage canister 16. In another method, called “fan folding,” the clinician bends the body tube in various ways in an attempt to break up any long clots and to facilitate flow to the canister. Any manipulation of a body tube in this fashion can be quite painful to the patient.
Another technique is known as “stripping.” In this technique, the clinician uses two or more lubricated fingers to compress, or pinch, the body tube near its entry point into the body. The clinician then slides the pinching fingers along the body tube, towards the drainage canister 16. Repeating this motion tends to move clots and debris toward the canister. This technique is only marginally successful. Further, the technique is known to generate short bursts of strong negative pressure at the ends of the body tube. This negative pressure causes a suction effect that can be dangerous because it can yield pressures of up to—300 cm of water adjacent to suture lines on, for example, coronary anastomosis. The resulting forces can damage the work that was done surgically during the operation. This damage is potentially life threatening.
None of these non-invasive techniques for removing debris from the body tube are uniformly successful, and all of them consume valuable time in the postoperative period. More-drastic methods also exist. These methods are more effective at cleaning—but more risky to the patient. In one scenario, a sterile field is made up, the body tube is disconnected at the coupler 12, and a suction catheter is run up the body tube to clear the debris.
This open-suction technique is generally effective, but it is highly undesirable for several reasons. First, it violates the sterile internal environment of the body-space drainage tube system, potentially introducing bacteria inside the patient's body. Second, for body tubes placed in the chest, it breaks the seal between the body tube and the canister, causing a loss of the physiologic negative pressure inside the chest. As a result, the lungs can collapse (pneumothorax) while body-tube cleaning is being carried out. Finally, it is time-consuming for the nurses or doctors to perform the procedure.
Because of the fear of clogging, clinicians often place more than one body tube, creating auxiliary drainage capacity but worsening pain and potential complications. After the patient makes it through the initial stage of recovery, when clogging can be life threatening, the patient is left with several large-diameter body tubes passing through skin, muscle, and other tissues to reach the body space to be drained or treated.
Chest tubes, for example, typically pass through the ribs of the chest wall, where the tubes lie next to the lung and along the pleura. This placement means that any movement, such as cough, is quite painful. Body tubes are also notorious sites for infection, and multiple tubes increase this risk. When the tubes are left in place for more than a day or so, clogging becomes an issue, as fibrin and other material form in the end of the tube, impairing its function. In support of these concepts, body tubes almost always have a significant clot in the distal end when removed. Any body tube left in place for several days will eventually fail (called a “dead tube”) due to clogging. To avoid the danger and hassle of dealing with clogged tubes, surgeons choose large-lumen body tubes and place multiple body tubes, especially after heart surgery, lung surgery, or trauma.
Solving the issue of clogging will allow body tubes to function with better safety and less nursing care. Devices and methods are needed in the art that effectively eliminates clogging and clotting in body tubes, reducing the need for painful and ineffective manipulations of the tubes, and thus reducing the trauma around the tube that can contribute to bleeding, tissue injury, and infection. A benefit will be that smaller body tubes, and perhaps fewer body tubes, can be used, since the reason to use the larger-diameter tubes is to facilitate evacuation of debris and clots that tend to more easily obstruct the smaller tubes. The net result will be reduced pain, faster recovery, and less cost.
Because larger body tubes require more specialty expertise to place, they are usually placed only by surgeons, with pulmonologists or others placing smaller, less effective body tubes. The availability of effective body tubes at smaller diameters will increase the number of clinicians who can insert and manage those tubes.